October 21, 2010

Despite the promising results of the "Placement of Aortic Transcatheter Valves (PARTNER) trial," featured in the Oct. 21 issue of the New England Journal of Medicine, a cardiothoracic surgeon from Boston Medical Center (BMC) believes that surgical aortic-valve replacement should remain the standard treatment of aortic stenosis. In the accompanying editorial, the author argues that Transcatheter aortic-valve implantation (TAVI) should be reserved for patients at inordinately high risk who are not suitable candidates for surgery and who have decreased life expectancy.

Aortic-valve replacement is the most effective treatment to alleviate symptoms and improve survival in patients with critical aortic stenosis. However, a substantial number of these patients have coexisting conditions that preclude surgery. Since outcomes with medical management are poor, a less invasive and safer alternative to surgical aortic valve replacement is needed for this expanding group of patients.

TAVI has emerged as an alternative treatment for aortic stenosis in patients who are considered to have a high or prohibitive surgical risk. In this week's Journal, Martin B. Leon and his coauthors report the results of the PARTNER trial, a prospective, randomized, multicenter trial to determine the optimal method of treating patients with critical aortic stenosis who are considered not to be suitable candidates for surgery. Patients who underwent TAVI as compared with patients receiving medical management, had a significantly lower rate of death at one year, fewer hospital readmissions, and a reduction in cardiac symptoms. These improved outcomes were achieved, however, at the cost of a significant increase in the rate of major strokes and vascular events.

"Now that there is evidence-based clinical data to substantiate the benefits of TAVI in patients who are not suitable candidates for surgery, there will be a temptation to expand this technology to all patients with aortic stenosis," said editorial author Harold Lazar, MD, a professor of cardiothoracic surgery and Director of the Cardiothoracic Surgical Laboratories at the Boston University School of Medicine (BUSM).

According to Lazar a number of issues must be resolved prior to deciding what role TAVI may play in the treatment of aortic stenosis including criteria to determine who is not a candidate for surgical aortic-valve replacement, who should perform TAVI and where should it be performed. "Only when these issues are addressed can we determine where we go from here," he stressed.

"Given what we know, TAVI should not be performed in patients with long life expectancies. Prospective, adequately powered, randomized trials comparing TAVI with surgical aortic-valve replacement in both high-risk and low-risk patients will be necessary to further define the role of TAVI in the treatment of aortic stenosis," he added.